Electric circuit breaker



March 28, 1939. s. RUPPEL ELECTRIC CIRCUIT BREAKER Filed Aug. 19, 1955 6 Sheets-Sheet 2 LLLUIMnvu l www 6 Sheets-Sheet 3 3kg,

Filed Aug. 19, 1935 @gf/A a Z Z fm/enfaz' March 28, 1939. 5 RUPPEL 2,152,283

ELECTRIC CIRCUIT BREAKER Filed Aug. 19, 1935 6 Sheets-Sheet 5 Hg. Il

o Ii lll sa E5 9 2| ii O y O jm/enzor..

March 28, 1939. s. RUPPEL ELECTRIC CIRCUIT BREAKER Filed Aug. 19, 1955 6 Sheets-Sheet 6 Patented Mar. 28, 1939 UNITED STATES ELECTRIC CIRCUIT BREAKER Sigwart Ruppel, Berlin, Germany; Frida Strauss, ne Ruppel, New York, N. Y., heir of Sigwart Ruppel, deceased Application August 19, 1935, Serial No. 36,859 In Germany August 25, 1934 14 Claims.

The invention relates to an electric circuitbreaker having means for extinguishing the arc by a pressure medium, in particular gas or vapour, of the kind in which the pressure is produced by the arc itself in a closed and preferably tubular chamber.

In the known circuit-breakers of this kind the extinction of the arc is effected by the blast of an extinguishing medium which flows under pressure. It is the more effective the higher the pressure of the blast gas. The pressure of the gas is the higher the greater the quantity of energy of the arc which is used for the development and heating of the gas (energisation). It is, therefore, difiicult to break a circuit in which a small currentl is flowing because in this case the energy of the arc is not sufficient for producing the necessary pressure of the blast gas in the relatively large switch chamber. The minimum dimensions of the switch chamber are limited by the dimensions of the electrode which is moved through the chamber, and for its part cannot be reduced below a certain size for reasons of rnechanical strength and by reason of the current which has to be conducted through it.

According to the present invention, a circuitbreaker of the aforesaid type is improved by the arrangement of a separate insulating piece or lling piece which reduces the cross-sectional area of the switch chamber in comparison with the internal area determined by the outer periphery of the movable electrode.

By this means not only is the pressure produced in the case of small currents increased owing to the reduction in the volume of the switch chamber, but the surface which is exposed to the arc is also increased in proportion to the cross-section, so that the arc comes into intimate contact with the surfaces which cool and de-ionise it. It is particularly advantageous to make the insulating lling pieces, and in some cases also the walls of the switch tube, of materials which give oi gas or vapour under the effect of the arc such, for example, as vulcanite or bre, since the increase in pressurethen-becom'es""s"till greater.

By means of the invention it is possible when disconnecting circuits carrying small currents to provide a narrow passage for the arc although the switch member has a cross-section of sufficient area for conducting large currents. Then, a switch having a single point of break and able to break a circuit carrying a large current can also be used for breaking a circuit carrying quite a small current. If the narrow passage through which the arc is drawn is provided, in accordance with a further feature of the invention, with a movable wall which, in the case of large currents, enables the passage to be enlarged owing to the pressure of the arc, then the switching range becomes particularly large.

For an effective extinction of the arc, in addition to the above-mentioned conditions, the following condition must also be fulfilled in a circuitbreaker in accordance with the present invention:-

As great a part of the arc as possible must be situated in the narrow switch chamber since the voltage gradient of the arc is high along the narrow switch chamber, and the arc effects the development of gas along the entire chamber.

In one form of construction in which these conditions are very largely fuliilled, the circuitbreaker consists of a tube of insulating material (switch tube) which represents the outlet passage of a closed auxiliary chamber which is employed for accumulating the blast gas under pressure. The switch tube and auxiliary chamber denne what might be conveniently termed a blind passage. The fixed contact is located in this auxiliary chamber. The movable Contact member closes the opening in the tube when in the switched-in position and also during the first part of the disconnecting process. -After the contacts have been separated the arc is drawn by the switch member into the switch tube. An insulating piece following the switch member moves out of the auxiliary chamber axially into the tube. The switch chamber which has now been formed and of which the walls are formed by the switch tube and the insulating piece introduced therein, can be so shaped, entirely independent of the cross-section of the switch member, that small and even the smallest currents can be extinguished with certainty. On the further movement of the switch member it moves out of the tube and suddenly frees the entire cross-section of the narrow switch chamber for the passage of the blast. The intensive blast which now follows, owing to the energy of the stored gas under pressure, effects the extinction of the arc during the first passage of the current through zero. If the lling piece is suitably dirnensioned an arrangement of this nature results in favourable conditions for extinguishing the arc for currents of all magnitudes from zero onwards.

Various constructional embodiments of circuitbreakers in accordance with the invention are illustrated by way of example in the accompanying drawings in which:-

Figure 1 is a longitudinal section through a circuit-breaker in accordance with the invention.

Figure 2 is a further form of construction, also in section, of a circuit-breaker in accordance with the invention which is suitable in particular for switches separating under load.

Figure 3 is a section through the switch chamber and the switch pin of a third form of construction.

Figure 4 is a modification of the form of construction shown in Figure 2.

Figure 5 is a section on the line I-I through the lling piece connected with the switch pin.

Figure 6 is a modification of the form of construction according to Figure 3 having a stationary filling piece.

Figure 7 is a further improved form of construction of a circuit-breaker in accordance with the invention,

Figure 8 is another form of construction having a damping resistance.

Figure 9 shows another form of construction of a switch chamber which, of course, may be used in any of the other circuit-breakers shown.

Figure 10 is a modification of the form of oonstruction shown in Figure 9.

Figure 11 is a form of construction in which the switch pin is fixed and in which the switch chamber is movable together with the counter contact located in it.

Figure 12 is a form of construction in which separate additional gases are employed and in which the switch chamber is provided with a separate outlet opening for the blast gases.

Figure 13 is a view, partly in section and partly in plan, showing a circuit-breaker with two break points connected one after the other and of column-like construction, and

Figure 14 is a circuit-breaker of column-like construction which is particularly suitable for high voltages and not very great currents.

Referring to Figure 1 of the drawings, the reference numeral I represents the stationary contact and 2 the pin-like movable contact of the circuit-breaker. The contact I is fixed in a cylindrical metal casing 3 which carries one of the terminals 4. An insulator 5 forms the switch chamber and carries at the same time the contact-making device. The circuit-breaker is shown fixed by means of a base plate 6 to a wall but any other suitable form of fastening could be employed instead of that shown. The insulator 5 is provided with a tubular part 'I in which the switch pin 2 moves with only a little play. The hollow chamber 8, which is hereinafter also termed the auxiliary chamber, acts as a chamber for accumulating the gas under pressure produced by the arc and deiines with the switch tube l a blind passage. In the cylindrical part 3 is arranged a pin 9 which is made of insulating material and under the action of the springs I0 follows the contact 2 during its disconnecting movement. 'I'he pin 9 acts as a filler for the switch tube 1 and reduces the cross-section of this tube when the contact 2 has moved out. The diameter of the lilling piece 9 is slightly less than that of the contact 2 and the piece itself is preferably made of a material which gives oir gas or vapour when acted upon by the arc, for example a material such as vulcanite or libre. It is preferable to keep the difference in diameter as small as possible in order that the gap in which the arc burns may be as narrow as possible. The narrowness of the gap is limited only by the condition that the filling piece must be able to move with ease in the tube 1. The gases and vapours which escape from the switch chamber are led away through the passage I I. The passage is turned through an angle of about in order that no gases may reach the parts situated below the switch chamber.

The pin contact 2 slides in a sliding contact I2 which is mounted on a metal plate or support I3 to which the second terminal I4 is connected. The part I3 is iixed to the base plate 6 by means of an insulator I5. On the base plate 6 is also mounted a lever I6 by which the contact 2 is operated and of which its shaft I1 is moved by any suitable form of driving mechanism which is not illustrated in the drawings. The insulator I8 which carries the switch chamber 5 may be made in one piece with the latter as illustrated or may consist of a separate part as is shown in Figure 2.

The method of operation of the apparatus is as follows. When the circuit-breaker is connected, the current lows from the terminal 4 through the metal body 3 to the fixed contact I and passes thence to the pin contact 2 through the sliding contact l2 and the supporting member I3 to the terminal I4.

When, on breaking the circuit, the contact 2 is moved downwards, the arc formed between the contacts I and 2 heats the air in the chamber 8 so that the pressure in this chamber is increased to a certain extent. The contact 2 then draws the arc downwards into the tube 'I whereby the pressure is still further increased particularly if the walls of this tube are made of a material which gives off gas or vapour on being heated. When the contact 2 comes out of the tube 'I a stream of compressed gas follows the contact 2 whereby if the pressure is suiiicient the arc is extinguished. The gases then escape through the passage II.

With the arrangement which has just been described, if a circuit carrying a small current is broken, the increase in pressure is not sul'- ficient to extinguish the arc. In this case the extinction of the arc is effected by means of the movable insulating pin 9 which follows the contact 2 into the switch tube 1. This pin reduces the cross-sectional area of the passage through which the gases escape from the auxiliary chamber 8 and thereby increases the flow at lower pressures. At the same time the available path for the arc through the tube "I is restricted and the arc is thereby brought into more intimate contact with the walls which consequently cool it to a greater extent and de-ionise it. Also the quantity of gas which is given off from the walls and from the filling piece 9 is increased owing to the intimate contact with the arc. Therefore, with this arrangement a circuit carrying a small current can also be broken with certainty.

The dimensions of the springs I0 are such that, taking into account the speed at which the contact 2 moves when the circuit is disconnected, the lling piece 9 is accelerated more slowly than the contact 2 and therefore follows it at a certain distance. This has the advantage that, in the case of large currents, during the extinction process or approximately during this process, the full cross-sectional area of the pipe I is at iirst available for the escaping gases whereby too great an increase of pressure in the switch tube and the auxiliary chamber 8 is avoided. The fact that the pressure of the arc opposes the movement of the insulating piece 9 assists this action still further. The movement of the filling piece 9 is therefore made dependent upon the current. Heavy currents are therefore extinguished at the full cross-section of the switch tube and, owing to the filling piece, the arrangement which is dimensioned so as to be suitable for the extinction of arcs produced by heavy currents is capable also of extinguishing to the best advantage arcs due to small currents.

When the connections are restored the switch member 2 returns the lling piece into its original position. On disconnecting the circuit the lling piece follows the switch member but at a certain interval which depends on the strength of the current. It is also possible to move the lling piece in the case of multi-phase circuit-breakers by means of a common earthed operating rod. The movement of the filling piece may then be released by the disconnecting movement at a suitably later time or the operating member of the filling piece may be moved with the operating member of the circuit-breaker after the latter has moved a certain distance.

Figure 2 shows a form of construction which is similar to Figure 1 which is suitable both for switches separating under load, switches with visible point of interruption for disconnecting the normal load, and also for overload-current power switches. The insulating iilling piece 9 is rigidly connected with the switch pin 2 and forms a prolongation of the pin. The lling piece 9 may contain a metal insertion 2l whereby the foot of the arc which, on disconnection, is seated on the arcing ring 22, is relieved from the influence of the electric field. The ring 22 is preferably made of a difficultly fusible material, for example of tungsten or a tungsten alloy. The insulating pin 9 is located, when the circuit is connected, in the auxiliary chamber B which is made as narrow as possible. Here again, the tube 1 and chamber 8 define a blind passage. The body` 5 of the switch tube, the stationary contact l, and' the lead or terminal 4, are carried by a metal body 23 which forms the auxiliary chamber 8 and is itself fixed and insulated from earth by means of the insulator I8. On disconnecting the switch, the movement takes place in an upward direction, that is to say in the opposite direction to the direction of movement in Figure 1, otherwise however the construction and the method of? operation is similar. The switch tube 1 is provided at the outlet end with a nozzle-like widened opening which increases the velocity of flow of the gases and simultaneously facilitates the introduction of the switch pin when making the connection. The tube 'l may be also of considerably more slender construction than is illustrated in the drawings.

When, on breaking the circuit, the insulating filling piece 9 enters the tube 1, the arc is constrained to burn in the narrow annular space between the insulating pin 9 and the wall 1 whereby an effective extinction is produced. The switch member may be drawn out to such a distance, as is illustrated by dotted lines at 9', that a free air gap is formed.

Since it is possible to increase the formation and energisation of the gas by causing the arc to burn for a longer period in the closed switch chamber, that is to say by moving the switch member more slowly, it is advantageous, in the case of circuit-breakers in which an increased extinguishing action is desired, to design the device so that the switching velocity is low,

namely about 1-3 meters per second, before the extinguishing blast occurs and to increaseit, if desired, after extinction in order to obtain better throttling. This method is particularly advantageous in the case of circuit-breakers which have not to disconnect very heavy currents, for example switches separating under load.' It is advantageous to increase the switching velocity with the current so that with heavy currents it is high and with small currents it is low. This can be eiected by means of additional electro# magnetic forces or by the pressure of the gas itself. In particular the movable Contact piece can be pressed upwardly like a piston by means of the pressure produced in the chamber. If the cross-section of the pin is suiiiciently great and the volume of the chamber is sufl'iciently small, the latter arrangement is the simplest if the pressure is suitably high.

Since when breaking a circuit which carries only a small current the auxiliary chamber is not necessary and may even impair the extinguishing conditions owing to the effect which it has inreducing the pressure, it is preferable to cut it off from the switch tube when disconnecting a circuit carrying a small current. For this purpose the filling piece can tightly shut off the auxiliary chamber from the switch tube at the beginning of the extinction of the arc in the case of a circuit carrying a small current. In the case of switches separating underload, the chamberf in which the contacts, the lling piece and so forth are located is preferably made as narrow'v as possible.

In Figure 3 the insulating pin 9 which is made of a material which gives off gas is stationarily arranged inside the hollow movable switch member 2. The walls of the tube 1 are likewise made of a material which gives olf gas but may, however, also be made of a material which does not give off gas. In order that the arc may embrace the lling piece 9, the latter may contain an' iron insertion. Since the lling pece can be easily replaced it may be made of a material which is eaten away by the arc in a short time. On the disconnecting movement of the tubular switch member 2 which takes place in an upward direction, a free annular space is formed between the switch tube and the filling piece 9 into which space the arc is drawn. The method of operation is therefore the same as in the case of the circuit-breaker shown in Figure 2 with the only difference that the lling piece remains continuously in the switch tube. The height of the filling piece is determined by the required duration of the development of gas as well as by the conditions of flow. The length illustrated in which the filling piece extends into the nozzle-like widened opening of the switch tube 'l produces a particularly advantageous flow of gas in the annular cross-section.

In the concentric arrangements which have hereinbefore been described the position of the path of the arc is fix-ed only in the longitudinal direction. Since the arc tends to maintain its approximately circular section, it does n-ct, for example, ll up the annular cross-sectional opening which is available for its passage but concentrates at one place. Under the influence of the current conductors and electro-dynamical forces it will generally prefer to take up, according to the current conductors and magnetic conditions in its vicinity, one position which is more strongly attacked than others. With a concentric arrangement a large part of the annular crosssection is left free as has been previously mentioned. The gas in this part is not energised to any considerable extent leither by the arc or by radiation or by conduction. Therefore, an arrangement is to be preferred in which the arc is constrained to burn at a denite place in the periphery of the tube. This object can be attained either by arranging insertions of a magnetic material in the wall of the switch tube or by an asymmetrical arrangement of the filling piece. Figures 4 and 5 illustrate arrangements of the latter kind.

As may be seen from the drawings in this form of construction which is otherwise similar to that of Figure 2, the filling piece 9 which is rigidly connected'with the switch pin 2 is provided over a certain part of its length with a groove 3| so that an approximately circular free space is formed by the filling piece and walls 'I of the switch tube in which the arc is trapped. When, on breaking the circuit, the iilling piece 9 enters the switch tube 1, the said circular cross-sectional space remains free for the passage of the arc and the gases which escape after the switch member 2 has moved out of the tube The arc is therefore quickly extinguished when a circuit carrying a heavy current is broken. The arc itself remains in the groove. The gases from the arc, however, enter into th-e annular cross-sectional space and produce an additional formation of gas therein. It is further advantageous to provide two or more grooves which are separated by means of ribs. The arc burns in one groove which can also be determined by the breaking place of the contact. The gases from the arc, however, pass through the annular space into the other grooves so that there the pressure gas can flow into the auxiliary chamber. Experiments have shown that with grooves of 10-50 mm2 even the smallest currents can be extinguished if the switch tube is about mm. long. The great-er the cross-section the longer must the tube be.

This arrangement is particularly advantageous if no very great currents have to be extinguished, for example in the case of switches s-eparating under load and switches for particularly high voltages and so forth. If an air gap is to be provided in such switches then, if the switch member is connected with the iilling piece, the lattermust be drawn out with the switch member. The extinction of weak current arcs is effected owing to the fact that in the further course of the switching movement the lower ungrooved end of the lling piece 9 almost completely fills the cross-section of th-e switch tube and thereby quenches or extinguishes the arc to a certain extent. Owing to the fact that the filling piece and the wall of the switch tube are made of substances which give off gas, these parts are protected from being destroyed by the arc` because the gases and vapours which are .evolved form a heat-insulating layer for the adjacent surfaces.

In the construction according to Figure 6 the filling piece 9 is stationary and an outlet passage II for the gases and vapour is provided similarly as in Figure 1. The special feature of this form of construction is the arrangement of an additional flap 35 which, under the action of the spring 36, closes the opening 38 through which the switch member 2 moves out of the body of the switch when the switch member has left this opening. This causes the are to be lengthened and drawn-in to a greater extent and aiiords an additional security for the extinction of the arc and for the prevention of blow-backs since no hot gases are able to follow the switch member when it moves out of the opening 38. The iiap 35 is also made of an insulating material which gives on gas for the purpose of increasing its life and producing a better extinguishing effect. The outlet passage is provided in this case with a separate cooling device which consists of metal partitions or the like and simultaneously acts as a silencer.

In Figure 7 one wall 40 of the switch tube 1 which is of rectangular cross-section is pressed by means of springs 4| against the switch member 2 or the insulating piece 9 in order to compensate for any material which is burned away or for other inaccuracies. The free space remaining between the insulating piece 9 and the wall 40 may be of any desired shape, for example of U-shape, of cross shape, or of double T-shape or of E-shape. In particular its cross-section can be reduced practically to zero by pressing the part 40 over its full width against the filling piece 9, since it also possesses the full Width of the switch tube. By the term width is meant the distance in the direction at right-angles to the plane of the drawings. 'I'he actual switch chamber then depends on the counter-pressure of the arc since when the current is large the part 40 is pressed outwards with a greater pressure than when the current is small.

In Figure 8 the currents are heavily damped by connecting a resistance 46 in series in the circuit to be interrupted so that a circuit carrying only a small current can always be broken. During the rst part of the switching movement th-e arc is taken by the switch member 2 to the inter mediate contact 4l. On the passage of the current through the zero point the arc is extinguished between the contacts and 41 and as the tension of the arc is already high owing to the formation of gas in the tube 48, is not again ignited. Then the extinction takes place in the manner previously described in the form of a small current extinction in the switch chamber which is formed by the switch tube and filling piece 9.

In Figure 9 the cross-section of the insulating filling piece 9 gradually increases whereby the transition from heavy current to low current extinction takes place gradually. The lengths of the insulating piece and so forth can be considerably greater than is illustrated in the drawings with the same cross-sectional dimensions. The switch member is provided with points 5|) made of a diiiicultly fusible metal such as tungsten or the like whereby the formation of metal vapour is greatly reduced.

The iilling piece 9 is porous and dips into a liquid 5| which is contained in the auxiliary chamber 8. Preferably the liquid is separated by an intermediate partition 52 from the actual auxiliary chamber 8 in order to prevent it from being thrown about, The level of the liquid can, however, also be so high that two contacts are immersed. The liquid which is drawn up by the filling piece 9 is evaporated in the switch tube 1 by the action of the arc so that the walls of the switch chamber need not give ofi any gases. The liquid also acts at the same time as a lubricant for reducing mechanical friction.

In Figure l0 there is a stationary filling piece 9 and a tubular switch member 2. The lling piece 9 is porous and impregnated with liquid which can be drawn from the container 5|. In order to enable the liquid to be drawn upwards more easily the filling piece 9 is provided with an axial bore into which wicks. 55 projects from the liquid 5|. In many cases the capillary action of the porous filling piece 9 is itself sufcient to draw up enough liquid.

Figure 11 shows a form of construction of the circuit-breaker according to the invention which has particular advantage both mechanically and also in respect to the conduction of the gases. The arrangement shown is of particular advantage when the filling piece has to follow the switch member at a certain distance after it. As distinguished from the arrangements which have been previously described, in this case both these parts are stationary and the switch chamber together with the auxiliary chamber and the ring contact are moved. The switch member 2 is structurally connected with the cooler or silencer 3'I. The movable part of the switch which consists of the switch tube 'I and the auxiliary container 23 moves downwards, when the circuit is broken, in the gas escape tube 56 which is at the same time provided with the lead or terminal I4 of the switch member 2 and may, for example, be made of hard paper, into the guide body 5l which also serves for conducting the current. For operating the switch a lever I6 is provided. The filling piece 9 is carried by a pin 58 which is introduced tightly at 59 into the auxiliary chamber container 23. On the downward movement of the switch part 'I-23, the opening I is freed by the switch member 2 when the blast occurs. The gases produced flow freely through the tube 56. A special feature of this form of construction is the metallic pin 60 with which the iilling piece 9 is provided and which is at the same potential as the contact I of the auxiliary chamber and on passing through this contact relieves the foot of the arc attached thereto from the electric iield when the current passes through the neutral point. The reference numeral I2 represents a sliding contact which passes the current from the metal casing 23 which carries the contact I to the metal casing 5l which is provided with the terminal 4.

The particular advantages of the arrangement according to Figure 11 are that the filling piece 9 and the switch member 2 are at a constant distance apart and the intermediate space is free from connecting or fastening members. The result of this is that the cross-section of the switch tube 'I is at rst entirely freed after the switch member 2 has moved out of it so that large currents can be extinguished or disconnected without an excessive rise in pressure occurring, Only then is the insulating piece 9 inserted into the switch tube 'I for extinguishing small currents.

In the arrangement according to Figure 12 the auxiliary chamber 8 is provided with a separate opening 65 for the blast. The chamber 8 is also connected, as in the other arrangement, with the switch tube l. The switch member 2 is moved into the tube 'I after the separation of the contacts while the filling piece 9 follows it directly, as illustrated, or at a distance. The extinction in this case also takes place by allowing the blast to escape out of the tube and the auxiliary chamber 8. In this case, however, the blast is set free by the filling piece 9 which at the moment when the pressure is produced closes the nozzle-like blow-off opening 65. This nozzle-like opening may be made of insulating material as is illustrated in the drawings. If this is the case the arc is formed into a loop under the influence of the blast. The entire nozzle can also be made of metal. Then one foot of the arc moves from the stationary contact I through the nozzle upwards. The contacts themselves may tightly close the opening 65 in particular when the movable contact 2 is resiliently constructed. rlhe auxiliary chamber 8 need not necessarily surround the switch tube l. The arrangement which has been illustrated has, however, the advantage that, on the switching movement, an increase of pressure takes place both on the inside and the outside of the tube so that the tube is subjected to much less stress owing to the increase of pressure within it than if it were surrounded by the atmosphere. It is even possible to provide in the tube openings for relieving the pressure in order to reduce the pressure in the interior of the tube to the pressure in the auxiliary chamber. Care must, however, be taken by providing projections, screens or the like, that the arc cannot strike around the tube. This arrangement of the auxiliary chamber can also be employed in the other forms of construction of the invention.

An insulating tube 66 which at the same time carries the switch body 61 can be employed in order to conduct additional gas under pressure to the switching place from the outside in such a Way that both blasts take part simultaneously in the extinction of the arc. In order to extinguish the arc it is sufficient to move the switch member to the position of the insulating iilling piece 9 which is indicated in dotted lines at 9. An air gap can also be provided by a completely drawing out the switch member with the insulating piece. An arrangement in which the insulating piece 9 remains in the tube while the switch member 2 is moved at the separating distance is, however, preferable. On breaking the circuit, the foreign gas can be mechanically compressed and can be used for the extinction oi small currents since from the auxiliary chamber, which may in some cases also act as a gascompression cylinder, it extinguishes small current arcs after the blast has been released. The switch tube and the lling piece are regulated relatively to one another in such a manner that they control the currents above them up to the limit. Small quantities of gas at low pressure are sufficient. If the blast with the foreign gas takes place after the extinction of large currents, for example owing to the filling piece releasing the inlet opening in the auxiliary chamber, it then acts to clean the switch gap.

It is suiicient if the foreign gas is employed for extinguishing purposes only with large currents for the purpose of increasing the power of the switch. Smaller currents are then extinguished in the manner described by means of the co-action of the switch tube with the filling piece. A reduced blast may then pass in particular in cases where the current is heavy. The stream of cold foreign gas protects the walls from giving off too much gas. The invention can also be used with advantage for switches or circuitbreakers for lower voltages, for example for motor switches, installation switches and the like.

Figure 13 shows a form of construction with series switching of two switch points which are of exactly similar construction. Each switch point is provided with a supporting insulator 'I0 which is mounted on` a common base plate 'II and carries the switch chamber. This consists of a metal intermediate piece 99 which carries the lead or terminal 'I2 and the fixed contact 'I3 and of the switch tube 'I4 as well as the filling piece 15, both of which are likewise fixed to the intermediate piece B9. The two movable switch members 16 are connected together by a cross-piece 11. Since the two switch members are at the same potential, the streams of gas escaping from the two switch tubes can strike in common the cross-piece 11. It is only necessary to provide partitions 18 between the switch points of different phases which, looking in the direction of the person viewing the gure, are to be considered to be situated one behind the other. The switch is driven by means of a rod 19 and crank from a shaft 8| which is driven in any desired manner.

If the filling pieces are not stationary but are movable, for example in the manner indicated in` Figure 1 or Figure 2, the insulators 1U can simultaneously form the auxiliary chambers (pressure accumulating chambers).

The form of construction shown in Figure 14 is specially suitable for high voltages and not very heavy currents, for example for switches separating underload. On the base plate 'H is mounted the insulator 10 which carries the iixed contact 13 together with the lead or terminal 12. The reference 14 represents the switch tube, 16 the movable contact which is connected with the insulating filling piece 15. The latter is acted upon by a compression spring 85. A stop B6 limits the travel of the switch member 16 since after a certain switching travel it abuts against the contact 13. The upper end of the switch member 16 carries a radiation cap` 81 and an air contact 88. The corresponding switch knife is revoluble about an axis and is mounted by means of a metal piece 9| with a lead or terminal 92 on a supporting insulator 93. The drive is effected by means of a rod 19 and crank 80 from a shaft 8|.

In the connected position, the current flows from the terminal 12 over the contacts 13 and 16 to the air contact 88 and thence by way oi the switch knife 89 and the part 9i to the terminal 92.

On breaking the circuit, the switch arm 89 is moved upwards by the driving rod 19. Since the spring pushes the switch member 16 and the lling piece 15 after it, the connection between the contacts 88 and 89 is at first maintained and the circuit is broken between the contacts 13 and 16. The lling piece 15 is pushed into the switch tube 14 until the stop 86 prevents the further movement of the parts 15 and 16. Then the switch arm 89 alone moves further and is thereby separated from the contact 88. There are, therefore, formed two arcs connected in series. The arc which burns in the tube 14 is extingished whereby the arc burning in the atmosphere is also extinguished. By this means with a relatively small length of the switch tube a large air gap is procured. The stop 86 is of piston-like construction and, on its upward movement, reduces the size of the pressure-accumulating chamber 94 located above it. By this means the blast effect of the gas flowing through the switch tube 14 is intensified and the extinction of the arc is correspondingly improved. The radiation cap 81 simultaneously serves as a deector for the escaping gases and keeps them away from the air contacts 88 and 89. In the disconnected position the parts 88 and 89 assume the position indicated in dotted lines by the references 88 and 89'.

The invention is not, of course, limited to the constructional examples shown in the drawings but can be modiiied as desired. It is also possible to use another pressure medium for extinguishing the arc instead of the gases or vapours, for example an insulating liquid. The processes for extinguishing the arc then take place within the liquid from which the extinguishing gases and vapours are produced. In this case, therefore, the production of gas from the walls of the switch tube or of the filling piece are only necessary when it is to be used for protecting the insulating parts from being attacked by the arc. In liquid switches the lower limiting current of the switch tube is lower than is gas switches. An insulating piece is, therefore, generally sufficient which only partly reduces the bore of the tube. The process according to the invention facilitates the construction of liquid switches for high voltages.

Each form of the invention contains what has been termed for convenience, a blind passage, dened by the switch tubes and their adjoining chambers. The significance of this term is a passage closed at one end permitting the accumulation or" pressure.

I claim:

l. A circuit breaker comprising a housing having a gas evolving wall and dening a passage, said housing being substantially closed to atmosphere during closed circuit conditions, said housing containing a gas accumulating chamber, a

conductive electrode closely tting said passage in said housing and freely relatively removable with respect to said housing, an insulating member imposed in said passage to limit the size of said passage, and a pair of terminals interconnected by said electrode during closed circuit conditions.

2. A circuit breaker comprising a housing containing gas evolving material, said housing being substantially closed during closed circuit conditions and defining a passage, a conductive electrode penetrating and closely iitting a passage in the housing, said terminal enclosed by said housing for rubbing contact with said electrode, said housing dening a switching chamber' adjacent to said terminal, said electrode and housing being relatively longitudinally movable and an insulating member imposed in said passage to limit the volumetric content of said passage.

3. A circuit breaker comprising a housing containing gas evolving material and defining a blind passage but otherwise closed to atmosphere, a terminal in said housing, a conducting electrode penetrating and closely fitting said passage and contacting said terminal during closed circuit conditions, said housing containing a gas accumulating chamber, means for relatively separating said electrode and housing to open said housing to atmosphere during open circuit conditions and an insulating member imposed in said passage for restricting the sectional area of said passage.

4. A circuit breaker comprising a housing containing gas evolving material and deiining a blind passage but otherwise closed to atmosphere, said housing containing a gas accumulating chamber, a conducting electrode closely iitting said passage and penetrating said housing during closed circuit conditions, means for relatively separating said electrode and housing to open said housing to atmosphere during open circuit conditions and an insulating member for restricting the sectional area of said passage, said insulating member having an actuating means separate from that of said electrode.

5. A circuit breaker comprising a housing containing a blind passage and being otherwise closed to atmosphere, gas evolving material in said housing, a conducting electrode closely tting said passage and penetrating said housing during closed circuit conditions, said housing containing a gas accumulating chamber, means for relatively separating said electrode and housing to open said housing to atmosphere during open circuit conditions and an insulating member for restricting the sectional area of said passage, said insulating member and said electrode having a common actuating means.

6. A circuit breaker comprising a housing, gas evolving material and in which a blind passage is deiined the housing being Aotherwise closed to atmosphere, a conducting electrode closely i'itting said passage and penetrating said housing during closed circuit conditions, said housing containing a gas accumulating chamber, means for relatively separating said electrode and housing to open said housing to atmosphere during open circuit conditions and an insulating member for restricting the sectional area of said passage, said insulating member being xed with respect to one of the relatively moving members.

7. A circuit breaker comprising a housing dening a blind passage and being otherwise closed to atmosphere, a conducting electrode closely fitting said passage and penetrating said housing during closed circuit conditions, said housing containing a gas accumulating chamber, means for relatively separating said electrode and housing to open said housing to atmosphere during open circuit conditions and an insulating member imposed in said passage for restricting the sectional area of said passage, said passage having a Wall of gas evolving material.

8. A circuit breaker comprising a housing containing a blind passage and being otherwise closed to atmosphere, a conducting electrode closely tting said passage and penetrating said housing during closed circuit conditions, said passage containing a gas accumulating chamber, means for relatively separating said electrode and housing to open said housing to atmosphere during open circuit conditions and an insulating member imposed in said passage for restricting the sectional area of said passage, said insulating member having a wall of gas evolving material.

9. A circuit breaker comprising a housing containg a blind passage and being otherwise closed to atmosphere, a conducting electrode closely tting said passage and penetrating said housing during closed circuit conditions, said housing containing a gas accumulating chamber, means for relatively separating said electrode and housing to open said housing to atmosphere during open circuit conditions and an insulating member imposed in said passage for restricting the sectional area of said passage, said insulating member and a Wall of said passage being composed of a gas evolving material.

10. A circuit breaker comprising a housing which is substantially closed during closed circuit conditions and containing a passage, a conductive electrode closely fitting said passage in the housing, gas evolving material in said housing, a terminal enclosed by said housing for rubbing contact with said electrode, said housing defining a switching chamber adjacent to said terminal, said electrode and housing being relatively longitudinally movable and an insulating member imposed in said passage to limit the volumetric content of said passage, said insulating member being actuated to move into said switching chamber during a break of the circuit.

11. A circuit breaker comprising a housing having a gas evolving wall and defining a passage, said housing being substantially closed to atmosphere during closed circuit conditions, a conductive electrode closely fitting said passage in said housing and freely removable out of said passage, a pair of terminals interconnected by said electrode during closed circuit conditions and an insulating member limiting the size of said passage ater the. circuit is broken.

12. A circuit breaker comprising a terminal and an electrode, a housing containing a gas evolving material and defining a passage for the reception of said electrode to close said housing to atmosphere during closed circuit conditions, means for completely separating said housing and electrode during a circuit breaking operation to release to atmosphere gas generated by the arc, said housing and its passage being so conformed as to direct all of the generated gases to follow the arc until the separating movement has opened the housing to atmosphere, and an insulating element having a smaller volumetric displacement than said electrode imposed in the path of the arc.

13. A circuit breaker comprising a housing dening a. passage, a closely iitting electrode received within said passage and closing the same under circuit making conditions, a pair of terminals interconnected by said electrode during closed circuit conditions, one of said terminals being located within said housing, means for relatively moving said electrode and housing during a circuit breaking operation to expose the resulting arc to a gas evolving material and to subsequently open said passage to atmosphere.

14. A circuit breaker comprising a housing having a gas evolving wall and dening a passage, a hollow conductive electrode closely fitting said passage in said housing, closing the housing under circuit making conditions and freely removable out of said passage, a pair of terminals interconnected by said electrode during closed circuit conditions and a member of gas evolving material within said hollow electrode for increasing the active gas evolving surface after the circuit is broken.

SIGWART RUPPEL.

.1"9 i CERTIFICATE 0E CORRECTION.

patent N. 2,152,285. march 28, 1959.

SIGWART RUPPEL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correetion'as follows: Page 6, second column, line hl, claim 2, for "a passage 'read said passage; line h2, same claim, for "said terminal? read a terminal; and that thesaid Letters Patont shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of June, A.' D. 1959.

mehr, van Arsdaie (Seal) Acting Commissioner of Patents.

bij 1J Patent No. 2,152,285. March 28, 1959.

scwART RUPPEL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 6, second column, line )41, claim 2, for "a passage fread said passage; line h2, san-.1e claim, for "said terminal" read a terminal; and that theaaid Letters Patont shouldbe read with this correction therein that the vsame may conform to the record of the case in the Patent Office.

signed and sealed this 6th day of' June, A.' D. 1959.

f1 E; L] 'CERTIFICATE oF CORRECTION.

henry vvan Arelaie (Seal) v Acting Commissigner. of Patents. 

